JP3501764B2 - Repair device and method for soil containing contaminants - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a remediation device for contaminated soil.
Installation and repair method.

[0002]

2. Description of the Related Art In recent years, as a solution to the environmental pollution problem, various attempts have been made to remove pollutants from soil contaminated with organic substances and restore the soil. There have been proposed methods such as a method in which a substance is sucked using a vacuum pump and treated with activated carbon, bioremediation using the degradability of microorganisms, and a method in which ultraviolet rays are irradiated to decompose the substance.

In the vacuum suction method, pollutants are removed by adsorption on activated carbon, but the adsorption efficiency on activated carbon is low, and it is difficult to treat substances containing a large amount of water. Furthermore, contaminants are adsorbed. This method is not always an efficient method because of the problem of reprocessing used activated carbon.

On the other hand, even in bioremediation, the decomposition activity expression and growth process of microorganisms are not always stable and the decomposition process may be relatively difficult to control. Particularly, it has not been put to practical use with regard to soil pollution of organochlorine compounds. In many cases.

As a device for decomposing pollutants, decomposition by light is known. This is a photolysis device that utilizes the phenomenon that UV rays of UV-B and C decompose some pollutants, and there are disclosed examples in JP-A-9-299753 and 10-180040.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to use water containing chlorine without the need for treatment with activated carbon or microorganisms, and to efficiently and efficiently remove polluted soil without the problem of secondary pollution. An object of the present invention is to provide an apparatus capable of performing treatment and an efficient method for repairing contaminated soil using the apparatus. Another object is to propose a simple pollutant gas purification device and a purification method using the same.

[0007]

A remediation device for contaminated soil according to the invention for achieving this object comprises a pollutant.
A soil remediation device that generates chlorine by aeration
The chlorine generation tank that can store the liquid and the soil extracted from the soil.
The pollutant and the chlorine generated from the generation tank
Means for mixing to obtain a mixed gas, and said mixed gas
Then, the mixed gas is irradiated with light to obtain the contaminants.
And a reaction tank for decomposing the quality.
It

Contaminants supplied to this contaminated soil restoration device
Extraction from quality soil contains pollutants from contaminated soil
Can be carried out by using a means for sucking the gas
As a drawing means, a combination of a pit formed in contaminated soil and a vacuum pump for sucking a gas containing a pollutant from the pit is preferably used.

As the chlorine generating means, a means for bringing air into contact with functional water capable of generating air containing chlorine by aeration is preferably used. Specifically, means for blowing air to the surface of the functional water, means for contacting the droplets with air in functional water (nozzle is a means for injecting example functional water), functional water means for aerated Yes, in the present invention
Is at least a means of aerating functional water with air.
It

Further, as the chlorine-containing air generating means, a water tank, a means for generating functional water, a means for introducing air into the water tank, a means for discharging the generated chlorine-containing gas, and a gas for generating chlorine-containing gas. Those equipped with a means for draining the functional water used in the above can be suitably used.

On the other hand, the method for repairing contaminated soil according to the present invention is
Aeration method for soil containing pollutants
The process of preparing a liquid that generates chlorine at
Aerated by aerating the extracted contaminants and the liquid
And chlorine to form a mixed gas,
After the process of obtaining the mixed gas, the mixed gas is irradiated with light.
And the step of decomposing the pollutants.
Characterize.

Extraction of pollutants from contaminated soil is
By inhaling gas containing pollutants from the soil
It can be carried out, preferably by means of a well formed in the contaminated soil and a vacuum pump for sucking gas containing pollutants from the well.

Further, as the step of generating chlorine,
A method of bringing air into contact with functional water capable of generating air containing chlorine by aeration is preferably used. Specifically, there are a step of blowing air to the surface of the functional water, a step of bringing the small droplets of the functional water into contact with air (for example, a step of ejecting functional water with a nozzle), and a step of aerating the functional water with air . In the present invention
Uses at least the step of aerating functional water with air.
It

Further, the step of generating air containing chlorine includes the steps of generating functional water, supplying functional water to a water tank, introducing air into the water tank, and discharging air containing chlorine generated. And a step of draining the functional water used for generating the air containing chlorine.

Further, the step of generating functional water to be supplied to the water tank may include a step of supplying water containing an electrolyte to the water tank and a step of applying a potential to the water containing the electrolyte in the water tank.

In the present invention, for example, first, air containing pollutants in the shaft is sucked by a vacuum pump or the like. Next, a liquid that generates chlorine by aeration
And aerated that functional water to generate a chlorine-containing air. The chlorine-containing air and the pollutant-containing air are mixed in the treatment tank, and light is irradiated. As a result, the pollutants are decomposed, and then the liquid components and the air are discharged,
Organic components such as trichlorethylene, which is a particular problem as a harmful substance, can be efficiently extracted from soil and decomposed.

[0017]

[0018]

[0019]

[0020]

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The basic structure of an embodiment of a disassembling apparatus according to the present invention will be described below with reference to FIG.

[Decomposition Reaction] (Apparatus Configuration) FIG. 1 is a schematic view of a contaminated soil restoration apparatus 1 according to an embodiment of the present invention. A vacuum pump 3 as suction means for sucking air in the vertical shaft 2 is arranged on the wall body surrounding the opening of the vertical shaft 2 of the contaminated soil restoration apparatus 1 of the present embodiment. Further, the vacuum pump 3 is connected via a blower 4 to a lower portion of a processing tank 5 that decomposes contaminants. The gas obtained from the soil sucked by the vacuum pump 3 is blown into the treatment tank 5 from the lower portion of the treatment tank 5 by the blower 4. This gas is usually in a state where volatile pollutants are contained in the air, but it may be composed of gas mainly containing pollutants.

Reference numeral 6 denotes an apparatus for producing water containing chlorine (functional water), from which water containing chlorine (functional water) is supplied to the treatment tank 5 through a pipe 7.

Contaminated air sent from the blower 4 is supplied from the gas supply port 8 into the processing tank. Contaminated air is ejected into water containing chlorine (functional water) as bubbles, and chlorine gas and pollutants are released to the air tank of the processing tank. Reference numeral 9 is a light irradiation means for irradiating the mixture of the pollutant and chlorine gas with light, and for example, a black light or the like may be used. Reference numeral 10 is a pipe for discharging purified polluted air. 11 is a pipe for draining the chlorine-containing water (functional water) used for the treatment. This tube should be made of a material that allows light to pass through, and when exposed to light, it decomposes pollutants dissolved in water containing chlorine.
If the purified polluted air discharged from 10 is below a predetermined concentration, it may be discharged as it is, or may be discharged to an activated carbon adsorption tower such as 19.

A known double vacuum extraction device or the like may be used as an example of the contaminant extraction device using the vacuum pump 3. Moreover, not only a vertical shaft but a horizontal well or the like may be used. In addition, by forming a well for vacuum extraction in contaminated soil, in-situ
In addition to repairing contaminated soil with, the contaminated soil can be purified and repaired by excavating the contaminated soil and sucking contaminants from the contaminated soil through pipes, etc. it can.

In the apparatus shown in FIG. 1, the chlorine-containing air generating means is such that water (functional water) containing chlorine is stored at the bottom of the treatment tank, and has a ventilation means for aerating air therethrough. Further, the air ventilated here contains pollutants, and this venting means also serves as a mixing means of the chlorine-containing air and the gas containing pollutants.

Further, in the apparatus shown in FIG. 1, water containing chlorine is used.
Gas (air) containing pollutants was introduced into (functional water) to generate air containing chlorine.However, using air containing chlorine obtained by contacting air with water containing chlorine (functional water), This may be mixed with a gas containing a pollutant in a closed area and then introduced into the light-irradiated processing area in the processing tank. The contact of air with water containing chlorine includes aeration of water containing chlorine (functional water), contact between small droplets of functional water and air (e.g., jetting with a nozzle), or air contact with the water surface. Introduction of
It can be done by (blowing).

In the means for generating chlorine-containing air when air is introduced into the gas phase, water is supplied / drained using a pump so that chlorine-containing water (functional water) is kept in a predetermined amount in a closed system container. Has been done. An air inlet and an outlet are provided in the gas phase portion in the closed system container, and when air is supplied from the inlet, the chlorine-containing gas in the gas phase portion in the container is expelled from the outlet. The air containing chlorine generated from the water containing chlorine (functional water) may be used for decomposition. Also in this case, the air containing a gas containing a pollutant may be used, and this may also serve as a mixing means of the chlorine-containing air and the gas containing a pollutant.

(Decomposition Process and Compound to be Decomposed) Next, the method for repairing contaminated soil according to the present invention will be described in detail. In recent years, pollution with persistent substances, particularly organic chlorides such as trichlorethylene, has become serious year by year, and establishment of an efficient and simple treatment method is desired. The treatment method using the contaminated soil restoration device 1 of the present invention is particularly performed with trichlorethylene.
(TCE), tetrachloroethylene (PCE), 1,1,1-
Trichloroethane, cis-1,2-dichloroethylene, tran
It is effective for treating organic chlorine compounds such as s-1,2-dichloroethylene, chloroethylene, 1,1-dichloroethylene, dichloromethane and trichloromethane. Although trichlorethylene and the like are accumulated in soil, it is possible to extract it from the soil in the gas phase by vacuum extraction. Therefore, the vertical shaft 2 is formed in the contaminated soil 18, and the air containing the contaminant such as trichlorethylene in the soil is sucked by using the vacuum pump 3. The air containing pollutants sucked from the contaminated soil 18 is blown into the treatment tank 5 from the lower part of the treatment tank 5 by the blower 4, and the water containing chlorine in the treatment tank 5 (functional water).
Pass through. Chlorine gas is discharged from water containing chlorine (functional water), and most of trichlorethylene and the like are also discharged to the gas phase. This is irradiated with light to decompose trichlorethylene and the like existing in a gas state, and the gas after being decomposed and removed is exhausted to the atmosphere.

(Regarding chlorine solution or functional water) The chlorine solution which can be used in the present invention has, for example, a hydrogen ion concentration (pH value) of 1 or more and 4 or less, preferably 2 or more and 3 or less, and a residual chlorine concentration of 5 mg / L or more and 300 mg / L or less, preferably 5 mg / L or more and 150 mg / L or less, more preferably 30 m
It should have a property of g / L or more and 120 mg / L or less. The redox potential is preferably 800 mV or more and 1500 mV or less when the working electrode is a platinum electrode and the reference electrode is silver-silver chloride.

More specifically, as shown in FIG. 1, the chlorine-containing air generating means stores water containing chlorine (functional water) at the bottom of the treatment tank, and the air ventilated therein collects pollutants. In the case where the aeration means also serves as a means for mixing chlorine-containing air and gas containing a pollutant, it is desirable that the residual chlorine concentration be in the above range.

An electrolyte (for example, sodium chloride or potassium chloride) is dissolved in raw water, and this water is electrolyzed in a water tank having a pair of electrodes to obtain a chlorine solution having the above-mentioned properties from the anode side. Obtainable.

The concentration of the electrolyte in the raw water before electrolysis is preferably 20 mg / L to 2000 mg / L for sodium chloride, and more preferably 200 mg / L or more and 1000 mg / L or less.

At this time, when a diaphragm is arranged between the pair of electrodes, it is possible to prevent the acidic water generated near the anode from mixing with the alkaline water generated near the cathode.

An ion exchange membrane or the like is preferably used as the diaphragm. And as means for obtaining such functional water, a commercially available strong acidic electrolyzed water generator (for example, trade name: Oasis Bio Half; manufactured by Asahi Glass Engineering Co., Ltd., trade name: strong electrolyzed water generator (Model FW- 200; Amano
(Manufactured by etc.) can be used.

This solution is called electrolyzed water, electrolyzed functional water, or functional water, and is used for the purpose of sterilization.

The chlorine solution having the above characteristics, that is, functional water, can be prepared from a reagent using hypochlorous acid or the like. For example, hydrochloric acid 0.001mol / L ~ 0.1mol / L,
It can be obtained by adjusting sodium chloride to 0.005 mol / L to 0.02 mol / L and sodium hypochlorite to 0.0001 mol / L to 0.01 mol / L.

It is also possible to prepare 2000 mg / L functional water having a pH of 4.0 or less and a chlorine concentration of 2 mg / L or more with hydrochloric acid and hypochlorite. For example, hydrochloric acid 0.001mol / L ~ 0.1
mol / L and sodium hypochlorite 0.0001 mol / L ~ 0.01
It can be obtained by setting mol / L.

Other inorganic or organic acids can be used in place of the above hydrochloric acid. As the inorganic acid, for example, hydrofluoric acid, sulfuric acid, phosphoric acid, boric acid and the like can be used, and as the organic acid, acetic acid, formic acid, malic acid, citric acid, oxalic acid and the like can be used. Functional water can also be produced by using N ₃ C ₃ O ₃ NaCl ₂ or the like, which is commercially available as a weakly acidic water powder generator (for example, trade name: KINOSAN 21X (manufactured by Clean Chemical Co., Ltd.)).

Further, water containing chlorine produced from a device having no diaphragm can also be used for decomposing the organic chlorine compounds described above. For example, the redox potential is 300
mV or more and 1100 mV or less, and chlorine concentration is 2 mg / L or more 1
It is less than 00 mg / L and has a pH of 4-10.

Water having a pH of 4 or more can be prepared not only by electrolysis but also by dissolving various reagents in raw water. For example, hydrochloric acid 0.001 mol / L to 0.1 mol / L, sodium hydroxide 0.001 mol / L to 0.1 mol / L, and sodium hypochlorite at a concentration of 0.0001 mol / L to 0.01 mol / L By including it, water containing desired chlorine can be obtained.

On the other hand, by using only hypochlorite, for example, sodium hypochlorite 0.0001 mol / L to 0.1 mol / L, water having chlorine concentration of 3000 mg / L or less and chlorine of pH 4 or more can be obtained. You can

As described above, mainly as shown in FIG. 1, the chlorine-containing air generating means stores water containing chlorine (functional water) at the bottom of the treatment tank, and the air aerated there is pollutant. It has been described that the ventilation means also serves as a mixing means of the chlorine-containing air and the gas containing the pollutant.

As will be described later, in the decomposition reaction according to the present invention, it is desirable that chlorine is in a certain concentration range at the decomposition site, and if the concentration range is achieved, water containing chlorine of the chlorine-containing air generating means ( The residual chlorine concentration in (functional water) does not necessarily have to be in the range shown above.

(Embodiment 3) For example, when the gas containing no pollutant is introduced into the water containing chlorine as shown in FIG. 3 and the generated chlorine gas and the air containing the pollutant are mixed, the above-mentioned residual It is desirable to make it higher than the chlorine concentration.

That is, in the configuration as shown in FIG. 3, the generated chlorine gas is diluted with air containing pollutants. This dilution ratio can be a ratio of the amount of chlorine gas generated and the amount of air containing pollutants supplied to the reaction field. For example, the supply of air containing pollutants is 4 times the supply of chlorine gas generated.
If doubled, the chlorine concentration is diluted to 1/5. It is necessary that a certain chlorine concentration range be maintained when diluted. For this reason, it is desirable to increase the residual chlorine concentration in the form as shown in FIG.

Functional water with higher residual chlorine concentration (chlorine solution)
Is easier to prepare from reagents than it is produced using electrolysis. That is, it is possible to easily obtain functional water having a residual chlorine concentration of 10 to 50 times obtained by electrolysis. It is controversial whether such a solution having a high residual chlorine concentration can be called functional water, but it is also called functional water in the present invention. When preparing such functional water having a high residual chlorine concentration with a reagent, it is preferable to mix hydrochloric acid and sodium hypochlorite solution in a chlorine generation tank rather than mixing the reagents in advance.

Examples of the raw water used for preparing the functional water include tap water, river water, sea water and the like. PH of these waters
Is usually between 6 and 8 with a chlorine concentration of at most 1 mg / L
However, such raw water naturally does not have the above-described ability to decompose organochlorine compounds.

(Concentration of Chlorine Gas and Means for Generating Chlorine Gas) It is possible to generate chlorine gas required for decomposition from the above chlorine solution, that is, functional water. As the gas containing chlorine gas, for example, air containing chlorine gas obtained by passing air through functional water can also be used. By mixing this with the gas to be decomposed and irradiating with light, the pollutant can be decomposed.

Alternatively, a mixed gas of the gas to be decomposed and chlorine gas may be obtained by passing air containing pollutants instead of passing air into the functional water. In this case, chlorine gas having a relatively high concentration can be obtained.

Regarding the mixing ratio of the gas to be decomposed and the gas containing chlorine gas, the concentration of chlorine gas in the gas is
It is preferable to adjust the concentration to be not less than 5 ppm and not more than 1000 ppm, and it depends on the concentration of the gas to be decomposed. In particular, the chlorine gas concentration in the mixed gas is 20 ppm to 500 ppm.
The decomposition efficiency of the gas to be decomposed becomes particularly remarkable below the range of 50 ppmV to 300 ppmV.

The generation and supply of such chlorine gas include the method by electrolysis and the preparation of chemicals as described above, but the chlorine gas cylinder, cartridge or the like is used to dilute the chlorine gas and directly supply it. You may obtain chlorine gas of the density of. That is, if the above chlorine gas concentration range can be realized, the optimum method can be selected according to the situation.

(Means for aerating functional water) When a gas containing a pollutant and / or an aeration gas is aerated in the functional water,
An air diffuser (bubbler) can be used. The air diffuser
Any conventional device used to blow gas into the liquid may be used, but it is desirable that the size of the bubbles be selected so that the surface area is sufficient for the vaporization of chlorine.

As the material of the air diffuser, it is desirable to select a material that does not react with the functional water component. For example, sintered glass, porous ceramics, sintered SUS31
6. A porous diffuser plate made of a net woven from fibrous SUS316 or a sparger made of glass or a pipe such as SUS316 can be used.

(Main Reaction Field of Decomposition Step) In one embodiment of the present invention, air is passed through the functional water to generate air containing chlorine gas necessary for decomposition. The part that allows air to pass through the functional water basically plays a role of supplying chlorine gas necessary for decomposition.
The gas phase reaction in the tank for the subsequent treatment and decomposition reaction is the main site of the decomposition reaction.

Therefore, when chlorine generation and decomposition reaction are integrated, the ratio of the gas phase part and the liquid phase part has a great influence on the decomposition ability. That is, if the volume of functional water increases, the amount of chlorine that can be supplied increases, but the gas phase part decreases and the reaction field for decomposition decreases. On the contrary, if the gas phase part increases, the reaction field increases and the decomposition reaction proceeds rapidly, but since the liquid phase part decreases, the supply of chlorine decreases.

Although there are various factors such as the speed of aeration and the supply speed of functional water, when the region of the generation of air containing chlorine and the decomposition reaction region (treatment region) are integrated, the liquid phase in the treatment tank is increased. 5% to 30%, preferably 10% to 20%
It is good to Even if they are not integrated, the ratio of the volume of the tank for generating air containing chlorine to the volume of the tank for carrying out the decomposition reaction is preferably about 1: 2 to 1: 9.

(Light Irradiating Means) As the light irradiating means that can be used in the present invention, light having a wavelength of 300 to 500 nm is preferable, and light having a wavelength of 350 to 450 nm is more preferable. The light irradiation intensity for chlorine gas and the decomposition target is, for example, several hundreds μW / cm ² (measured between 300 nm and 400 nm) with a light source having a peak around a wavelength of 360 nm, and the decomposition is practically sufficient.

Natural light is used as a light source for such light.
(For example, sunlight etc.) or artificial light (mercury lamp, black light, color fluorescent lamp, short wavelength (500 nm or less) light emitting diode etc.) can be used.

Further, as shown in FIG. 1, when the water containing chlorine used for the treatment is drained, the drain may be irradiated with light, but the wavelength, intensity, and light source of the light irradiation used at this time are also as described above. It is desirable to use a light irradiating means having the above property.

(Reaction Tank) Although any form may be used to physically limit the treatment area for the decomposition treatment, as described above, the purification reaction according to the present invention can be performed with light containing no light of 300 nm or less. Since it is not necessary to pass light of 300 nm or less, it is possible to use glass, plastic, etc.

As a result, an inexpensive system can be achieved.

By increasing the selection of materials, the degree of freedom in selecting the form and shape of the reaction tank is increased. For example, as described in detail in Examples 6 and 7 below, a bag-shaped one such as an air bag can be used as the reaction tank.

Light required for decomposition as a bag-like reaction tank (300 nm
Or more, or 350 nm or more), but any form may be used, but a Tedlar (TEDLAR: Du Pont Co., Ltd.) bag or a fluororesin bag using a polyvinyl fluoride film has a gas adsorption / permeability surface. Is preferred.

Some types of fluororesin bags are 300 nm
Some of the following light are transmitted, and the bag-shaped reaction tank of the present invention can be used for reactions in which light of this wavelength is essential.

By using the bag as a reaction tank, not only the apparatus becomes cheaper, but also because it is lightweight, it is easy to install and move equipment on the treatment site.

Further, the bellows structure facilitates folding.

Since it is easy to change the size of the reaction tank according to the decomposition conditions in the bellows structure and the bag-shaped reaction tank,
The optimum residence time (reaction time) can be variably set according to the situation.

The bag-shaped reaction tank described above can be used for decomposing and removing pollutant gas other than treating pollutants sucked from soil. For example, it can be used for purification of pollutant exhaust gas discharged from factories in chemical processes, treatment of pollutant gas desorbed from activated carbon, pollutant gas generated by aeration of polluted water, and the like.

(Decomposition Reaction Mechanism) The present inventors have already found that the light irradiation in the presence of chlorine gas causes the decomposition of the organochlorine compound to proceed, but the reaction mechanism was largely unknown. However, it is already known that chlorine is dissociated to generate radicals when it receives light with a wavelength in a specific range. Also in the present invention, it is considered that chlorine radicals are generated by light irradiation and react with the substance to be decomposed to break the bond.

Oxygen is essential in the reaction of the present invention, but it is sufficient if oxygen radicals generated by the decomposition of chlorine and water and normal oxygen in the air are present.

[0072]

The present invention will be described in more detail below.

(Example 1) The contaminated soil restoration apparatus of the present invention will be described in detail.

At the site contaminated with TCE and PCE, the effect of the contaminated soil repair apparatus of the present invention shown in FIG. 1 was confirmed.

When soil suction (vacuum extraction method) was carried out from soil 18 contaminated with TCE and PCE according to a known method, the initial concentration of TCE was 700 to 900 ppm and the initial concentration of PCE was 300 to 700 ppm. This contaminated air was blown into the treatment tank from the lower part of the treatment tank, and the TCE and PCE existing in the gaseous state in the air were decomposed and removed by irradiation with light.

Water containing chlorine (electrolyzed acidic water) was supplied at 50 mL / min from Oasis Bio Half (manufactured by Asahi Glass Engineering Co., Ltd.) into the treatment tank, and polluted air was 100 mL / m.
Gushed into the water at in. 50% chlorine-containing water from the treatment tank
It was discharged at mL / min so that the amount (volume) of water containing chlorine was always 8 to 12% of the treatment tank. The light irradiation in the treatment tank is a black light fluorescent lamp (Toshiba, FL10 BL
B, 10 W). Irradiation energy is approximately 0.2
It was ˜0.6 mW / cm ² . TCE in the discharged gas,
The PCE concentration was measured by gas chromatography with a FID detector (trade name: GC-14B; Shimadzu Corp. column, J & W DB-624 column). As a result, TC in the exhaust gas
The E and PCE concentrations were 2 ppm or less, and it was found that the apparatus according to the present invention can highly decompose and remove TCE and PCE.

(Example 2) At the same site as in Example 1, the effect of the contaminated soil repairing apparatus according to another embodiment of the present invention was confirmed.

In this embodiment, instead of using electrolyzed water as water containing chlorine, in this embodiment, a solution containing hypochlorous acid (hydrochloric acid 0.006 mol / L, sodium chloride 0.01
mol / L, and sodium hypochlorite 0.002 mol / L, p
H 2.3) was used. Other than that, the same experiment as in Example 1 was performed.

That is, in this embodiment, the device shown in FIG. 2 was used as the means 6 for producing water containing chlorine. 21 in the figure
Is a tank that stores a solution containing hypochlorous acid and is supplied to the mixing tank 22 in a predetermined amount. 23 is a tank for storing a solution containing an acid. Here, hydrochloric acid is used, and a predetermined amount of the hydrochloric acid is supplied to the mixing tank 22. Raw water is supplied from the supply pipe 24 to the mixing tank 22, where the solution containing hypochlorous acid,
A solution containing hydrochloric acid and raw water are mixed, and "water containing chlorine"
(Functional water) is generated. This water is discharged through pipe 25. 26 is a stirring means.

TCE and PC in the gas discharged after the treatment
Chromatography with EID detector for E concentration (trade name: G
C-14B; manufactured by Shimadzu Corporation, column is DB manufactured by J & W-
624). As a result, TCE and PC in the exhaust gas
The E concentration is 2 ppm or less, and the T
It was found that CE and PCE can be highly decomposed and removed.

Example 3 In Examples 1 and 2, air containing pollutants was introduced into water containing chlorine to mix gas containing chlorine and pollutants. In this example, however, water containing chlorine was contaminated. Chlorine gas generated by introducing a substance-free gas is mixed with air containing pollutants.

FIG. 3 is a schematic diagram of this embodiment. Vertical shaft 2 is formed in contaminated soil 18 and vertical shaft 2 of contaminated soil restoration device 1 is formed.
A vacuum pump 3 for sucking air in the vertical shaft 2 is arranged on a wall surrounding the opening. Furthermore, the vacuum pump 3
A blower 4 is connected to the lower part of a processing tank 5 for decomposing pollutants. That is, the pollutants in the polluted soil 18 are sucked by the vacuum pump 3, and the air containing the pollutants is blown by the blower 4 from the lower portion of the treatment tank 5 to the treatment tank 5.
It is blown inside.

Reference numeral 6 is an apparatus for producing water containing chlorine,
From here, water containing chlorine is supplied to the chlorine generation tank 12 through the pipe 7. Air is blown into the chlorine generation tank 12 from the lower part of the chlorine generation tank 12 by the blower 13.
The air sent from the blower 13 through the 14 air supply ports is supplied into the chlorine generation tank 12. The air is ejected as air bubbles into water containing chlorine, and the air containing chlorine gas is released to the air tank portion of the chlorine generation tank 12. This chlorine-containing gas is sent to the processing tank 5 via the pipe 15. The contaminated air sent from the blower 4 from the gas supply port 8 is supplied into the processing tank and mixed therewith. Reference numeral 9 is a light irradiation means for irradiating a mixture of pollutants and chlorine gas with light,
For example, black light may be used. Reference numeral 10 is a pipe for discharging purified polluted air. 11 is a pipe for discharging water containing chlorine used for the treatment. The volume of the chlorine generation tank 12 was set to 20% of the volume of the treatment tank 5.

In the case of this apparatus, the air containing chlorine and the gas containing the pollutant are mixed in the processing region of the processing tank, and the gas mixing means is formed by the constituent members including the pipe 15 and the like necessary for this mixing. ing.

At the same site as in Example 1, the effect was confirmed by using the contaminated soil restoration apparatus as shown in FIG. In this example, the same experiment as in Example 1 was conducted using electrolyzed water similar to that in Example 1 as water containing chlorine.

TCE and PC in the gas discharged after the treatment
Chromatography with EID detector for E concentration (trade name: G
C-14 B; Shimadzu Corp. column, J & W DB column
-624). As a result, TCE, P in the exhaust gas
The CE concentration was 2 ppm or less, and it was found that the apparatus according to the present invention can highly decompose and remove TCE and PCE.

In the configuration of this embodiment, the gas containing chlorine is sent to the processing tank 5 through the pipe 15, but is supplied between the pump 3 and the blower 4 to process the mixed gas from the blower 4. It may be supplied to the tank 5.

(Example 4) In Examples 1 to 3, pollutants were sucked from the polluted soil, but in this example, the polluted soil was purified by passing a pipe through the polluted soil excavated from the polluted soil.

In FIG. 4, 17 is excavated contaminated soil, 16 is a pipe, and the contaminants in the contaminated soil are sucked by the pump 3 and sent to the treatment tank for decomposition.

Contaminated soil contaminated with organic chlorine compounds etc. 17
Was purified using an apparatus as shown in FIG. The pollutant components and concentrations of the polluted soil were as follows. Trichlorethylene concentration: 11.3 mg / kg Tetrachlorethylene concentration: 8.1 mg / kg Dichloromethane concentration: 2.3 mg / kg 1,1,1-Trichloroethane concentration: 8.3 mg / kg Experiments similar to those of Example 3 except using excavated contaminated soil When the concentration of pollutants was measured by the same method as above, the concentration of pollutants from the discharge pipe 10 was below the measurement limit, and the concentration of pollutants in the contaminated soil after treatment was 0.01%. It was below mg / kg. As a result, it was confirmed that the polluted soil was purified and the pollutants released from the polluted soil were also decomposed.

(Example 5) In Examples 1 to 4, a light source of 300 nm to 500 nm is used as a means for irradiating light, but in this Example, a light source having a peak at 254 nm (sterilizing lamp) is used.
Was used to purify the contaminated soil. Instead of the black light, a light irradiation unit in which a sterilizing lamp was inserted in a quartz tube was installed in the processing tank 5 and an experiment was conducted with the same device configuration as in Example 3 except that the processing tank was irradiated with ultraviolet light. When decomposing ability is compared between when chlorine-containing air is generated from chlorine-containing water and when chlorine-containing gas is not generated and mixed only with air, chlorine gas is used even when a germicidal lamp is used. The form in which was added had a decomposition ability of 2 to 10 times better. Further, in the case of decomposition at a low concentration of about 10 ppmV, the form in which chlorine gas was added could be decomposed to a lower concentration, and the decomposition rate could be increased.

(Sixth Embodiment) FIG. 5 is a schematic view of the present embodiment. A vertical shaft 2 is formed in the contaminated soil 18, and a vacuum pump 3 for sucking air in the vertical shaft 2 is disposed on a wall body surrounding the opening of the vertical shaft 2 of the contaminated soil restoration apparatus 1. Further, the vacuum pump 3 is connected to a reaction bag 30 that decomposes contaminants via a blower.

27 is a means for supplying chlorine. Although this may be the chlorine generation tank 12 as in Example 3, a chlorine cylinder is used in this example. Chlorine gas was supplied into the reaction bag 30 so that the desired concentration was obtained. That is, the pollutants in the polluted soil 18 are sucked by the vacuum pump 3, and the air containing the pollutants is mixed with the chlorine gas from the chlorine cylinder 27 in the reaction bag 30. Reference numeral 9 is a light irradiation means for irradiating the mixture of the pollutant and chlorine gas with light, and for example, a black light or the like may be used.

Reference numeral 10 is a pipe for discharging purified polluted air.

The reaction bag 30 may be in any form as long as it satisfies the following requirements. 1) Does not permeate the content gas. 2) Transmit light with a wavelength of 300 nm or 350 nm or more. 3) It has the strength to withstand the air volume.

Further, it is desirable that no adsorption occurs, but a slight degree does not cause any problem.

Soil suction (vacuum extraction method) was carried out from a soil 18 contaminated with TCE, PCE and dichloromethane according to a known method, and the initial concentration of TCE was 100 to 150 pp.
The initial concentration of PCE was 30 to 50 ppm, and the initial concentration of dichloromethane was 30 to 50 ppm. Using this contaminated air, the effect was confirmed using a contaminated soil restoration device as shown in FIG. In this example, a chlorine cylinder was used as a chlorine supply source, and a Tedlar bag (manufactured by GL Sciences Inc., total volume: 3 m ³ ) was used as a reaction tank (reaction bag 30).

The reaction bag is very different from a structure formed of a metal or glass housing, and can be folded and stored when not in use, and is easy to carry.
Also, it can be easily installed at the pollution restoration site. After installation, it is only necessary to arrange a light illumination system and secure a gas flow path, and it is easy to remove the equipment after the completion of repair.

Chlorine was supplied from a chlorine cylinder so that the chlorine concentration was 100 ppmV. The pollutant gas was supplied in such an amount that the residence time was 1 minute. The light irradiation is performed from both sides of the Tedlar bag as shown in the schematic FIG.
L40S BLB).

TCE and PC in the gas discharged after the treatment
The E and dichloromethane concentrations were measured by chromatography with a FID detector (trade name: GC-14B; Shimadzu Corp. column, J & W column DB-624). As a result, the concentrations of TCE, PCE and dichloromethane in the exhaust gas were below the measurement limit, and the TCE, PC
It was found that E and dichloromethane can be decomposed and removed to a high degree.

FIG. 6 shows a structure in which this soil restoration device is covered with 28 outer containers. Such a form is desirable outdoors such as at a pollution site.

(Embodiment 7) FIG. 7 shows an example in which the structure using the outer container 28 shown at the end of Embodiment 6 is integrated as a processing apparatus.

The outer container 28 corresponds to a processing tank, and a mixed gas of air containing pollutants and chlorine gas necessary for decomposition is introduced through a pipe 29. The treatment tank is an outer container 28
A reaction bag 30 and a light irradiation means 9 are provided in the inside.

The mixed gas introduced into the reaction bag is irradiated with light by the light irradiation means 9, decomposed and purified, and discharged from the exhaust pipe 10.

By adopting a constitution in which the decomposition reaction is carried out in the reaction bag, it is possible to cut off the contact between the processing tank (outer container) and the light irradiation means and the reaction gas, and the corrosion due to the decomposition is not affected. End

When the reaction bag is used for a long period of time beyond its durability, only the reaction bag can be replaced.

[0107]

EFFECTS OF THE INVENTION By carrying out the method for remediating contaminated soil using the contaminated soil remediation device of the present invention, there is no need for treatment with activated carbon, there is no problem of secondary contamination, and control of activity control caused by using microorganisms is carried out. It shows the excellent effect that the contaminated soil can be efficiently treated in-situ without the need to perform. It is also possible to clean up excavated contaminated soil.

A bag-shaped processing tank having a variable shape and volume can be used. In this case, the following effects are further obtained. (1) The device becomes cheaper. (2) Since it is lightweight, it is easy to install and move equipment at the treatment site. (3) The bellows structure facilitates folding. (4) Since it is easy to change the size of the reaction tank according to the decomposition conditions in the bellows structure and the bag-shaped reaction tank, the optimum residence time (reaction time) can be variably set according to the situation.

Further, the bag-shaped treatment tank can be applied not only to the purification of contaminated soil, but also to the decomposition treatment of contaminated exhaust gas, contaminated gas desorbed from activated carbon, and aerated contaminated water.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a polluted soil purifying apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic view of a means for producing water containing chlorine used in the present invention.

FIG. 3 is a schematic view of a polluted soil purifying apparatus according to another embodiment of the present invention.

FIG. 4 is a schematic view of a polluted soil purifying apparatus according to another embodiment of the present invention.

FIG. 5 is a schematic view of a polluted soil purifying apparatus according to another embodiment of the present invention.

FIG. 6 is a schematic view of a pollution control device according to another embodiment of the present invention.

FIG. 7 is a schematic view of a polluted gas purifying apparatus according to an embodiment of the present invention.

[Explanation of symbols]

1: Contaminated soil restoration device 2: Vertical resistance 3: Vacuum pump 4: Blower 5: Treatment tank 6: Water generator containing chlorine (functional water) 7: Pipe 8: Gas supply port 9: Light irradiation means 10: Discharge pipe 11: Discharge pipe, drain pipe 12: Chlorine generation tank 13: Blower 14: Air supply port 15: Pipe 16: Pipe 17: Contaminated soil 18: Contaminated soil 19: Activated carbon adsorption tower 21: Tank for storing a solution containing hypochlorous acid 22: Mixing tank 23: Tank for storing solution containing acid 24: Supply pipe 25: Pipe 26: stirring means 27: chlorine supply means 28: Outer container 29: Pipe 30: Reaction bag

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI C02F 1/46 B09B 5/00 ZABS C07B 37/06 B01D 53/34 134E (56) Reference JP-A-9-234338 (JP, A) JP 2000-5740 (JP, A) JP 2000-15238 (JP, A) JP 54-118646 (JP, A) JP 59-9212 (JP, B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) B01D 53/70 B01J 7/02 B01J 19/12 B09C 1/00 C01B 7/01 C02F 1/46 C07B 37/06

Claims (6)

(57) [Claims] 1. A repair device for soil containing pollutants.
The chlorine generation that can store the liquid that generates chlorine by aeration
The raw tank, the pollutant extracted from the soil , and the
Hands for mixing with the above-mentioned live chlorine to obtain a mixed gas
And irradiating the mixed gas with light after obtaining the mixed gas.
And a reaction tank for decomposing the pollutants.
And a soil remediation device containing pollutants. 2. A liquid which generates chlorine by the aeration.
To the anode side by electrolyzing water containing electrolyte.
The restoration according to claim 1, wherein the restoration is generated water.
apparatus. 3. The light does not include a wavelength of 300 nm or less.
3. The repair according to claim 1 or 2, wherein the light is bright light.
Recovery device. 4. A method for repairing soil containing pollutants.
A step of preparing a liquid that generates chlorine by aeration , and aerating the contaminant and the liquid extracted from the soil
The resulting chlorine is mixed to form a mixed gas
After the steps and the step of obtaining the mixed gas, the mixed gas is exposed to light.
Irradiation to decompose the pollutants.
A method for remediating soil containing pollutants, which comprises: 5. A liquid that generates chlorine by the aeration.
To the anode side by electrolyzing water containing electrolyte.
Repair according to claim 4, characterized in that it is produced water.
Method. 6. The light does not include a wavelength of 300 nm or less.
6. The repair according to claim 4 or 5, characterized in that it is bright light.
How to recover.